The date and time shown in visit details are always according to the timezone of the connected Google Analytics View.
You can check the timezone of your Google Analytics View by navigating to your settings:
STEP 1: Click your name on the right upper corner and selecting Settings for... from the menu.
STEP 2: Timezone is displayed under Website settings.
STEP 3 OPTIONAL:
You can manually set your timezone in these settings if needed. Keep in mind this will have an effect on most of the dates presented in the interface (including visit times). If you work with a company that crosses multiple time zones you may want to decide on one together.